Individual letter – 401 Squadron

Hi all,

Could anyone help me find the individual letter carried by the following aircraft while flying with 401 Squadron? Most of them were issued to 401 in July-August-September-October-November of 1942, before being re-issued to 403 Squadron on 25 January 1943.

Spitfire IX:

– BR628 YO*?
– BR630 YO*?
– BR951 YO*?
– BR981 YO*?
– BR985 YO*?
– BR986 YO*?
– BS145 YO*?
– BS157 YO*?
– BS172 YO*?
– BS176 YO*?
– BS183 YO*?
– BS202 YO*?
– BS277 YO*?
– BS311 YO*?
– BS317 YO*?
– BS383 YO*?
– BS391 YO*?
– BS474 YO*?
– BS534 YO*?
– EN129 YO*?
– EN130 YO*?

Thanks in advance,

Fox.